Check the paper guides and paper settings for the trays. If you are printing from a computer, check the paper settings under your copier preferences as well. If you are using thicker paper, make sure you have selected the appropriate thickness setting on both the copier and the computer. You may also want to try a new ream of paper--sometimes moisture in the paper can cause paper jamming issues. If the paper is being damaged during the jam, check the paper path for torn paper and/or foreign objects.